European Union competition commissioner Neelie Kroes has slammed comments from the US department of justice on a European court ruling on an antitrust judgment against Microsoft.

Kroes described the criticism of the ruling as "totally unacceptable" during a news conference in Brussels.

The DOJ's assistant attorney general for antitrust, Thomas Barnett, criticised the ruling sharply, warning that it could "have the unfortunate consequence of harming consumers by chilling innovation and discouraging competition."

Kroes fired back: "I think it is totally unacceptable [that a representative of the US government] should criticise an independent court's decision. The Commission does not pass judgement on rulings in US courts. We expect the same respect," she said.

On Monday the Court of First Instance, Europe's second-highest court, dismissed an appeal by Microsoft against the Commission's 2004 antitrust ruling against the company.

The DOJ statement added: "In the United States, anti-trust laws are enforced to protect consumers by protecting competition, not competitors". Barring "demonstrable consumer harm, all companies, including dominant firms, are encouraged to compete vigorously."

Kroes, who plans to visit Washington, said that if Microsoft is unhappy with the court ruling it should appeal it to Europe's top court, the Court of Justice.